Low energy magnetic actuator

• US 7,656,257 B2
• Filed: 09/26/2005
• Issued: 02/02/2010
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Steorn Limited
• Original Assignee: Steorn Limited
• Inventors: McCarthy, Shaun David, Daly, Michael Andrew, Simpson, Alan
• Primary Examiner(s): Enad; Elvin G
• Assistant Examiner(s): Rojas; Bernard
• Application Number:
  US11/235,423
• Publication Number:
  US 20060066428A1
• Time in Patent Office: 1,590 Days
• Field of Search: 335220-229, 200/5.R, 200/47, 310/12, 310/14
• US Class Current: 335/207
• CPC Class Codes: E05B 2047/0007 with two or more electromagnets
• CPC Class Codes: H01F 7/0205 Magnetic circuits with PM in general
• CPC Class Codes: H01F 7/0252 PM holding devices H01F7/021, H01F7/0215, H01F7/0226 take precedence
• CPC Class Codes: H01H 36/008 Change of magnetic field wherein the magnet and switch are fixed, e.g. by shielding or relative movements of armature for reed switches H01H36/002

Abstract

A low energy magnet actuator allows magnetic fields to be turned on and off using a small amount of energy. The magnetic actuator according to the invention generally includes a base suitable for the support of a plurality of magnets. An actuatable shield is positioned in relation to the plurality of magnets so that it effectively blocks the magnetic field when it is positioned over at least one of the magnets. The magnetic fields of the plurality of magnets interact in a manner that allows low energy actuation of the shield.

Claims

1. A magnetic actuator, comprising:

a base;

a first magnet disposed on the base in a first position and having a first magnetic axis oriented perpendicularly to the base;

a second magnet disposed on the base in a second position relative to the first magnet and having a second magnetic axis oriented perpendicularly to the base; and

a shield that is movable along said base in a plane that is perpendicular to said first magnetic axis and said second magnetic axis, and configured for actuation between a first position and a second position, when the shield is in the first position it substantially blocks a magnetic field emanating from the first magnet and leaves a magnetic field emanating from the second magnet substantially exposed, and when the shield is in the second position it substantially blocks a magnetic field emanating from the second magnet and leaves a magnetic field emanating from the first magnet substantially exposed.

2. The magnetic actuator of claim 1 characterized in that each of the first magnet and second magnet is of similar field strength.

3. The magnetic actuator of claim 1 characterized in that the field that radiates from the ends of the first magnet and the second magnets is of the same polarity.

4. The magnetic actuator of claim 1 characterized in that the shield is of a thickness that effectively blocks the emitted magnetic field when positioned over one of the first magnet and the second magnet.

5. The magnetic actuator of claim 1 fun her comprising a linear bearing and the shield is disposed on the linear bearing and moves relative to the base.

6. The magnetic actuator of claim 1 wherein the first magnet is fixed to the base.

7. The magnetic actuator of claim 1 wherein the second magnet is fixed to the base.

8. The magnetic actuator of claim 1 further comprising a third magnet disposed on the base.